The present invention relates to a digital encoding process for transmitting and/or storing accoustical signals and, in particular, music signals which scanned values of the acoustical signal are transferred by a transformation or a filter bank into a sequence of second scanned values which reproduce the spectral composition of the acoustical signal. The sequence of second scanned values is quantized in accordance with the requirements with varying precision and is partially or entirely encoded by an optimum encoder. A corresponding decoding and inverse transformation takes place during the transformation.
Processes such as those described above are known, by way of illustration, from DE-PS 33 10 480 or from WO 88/01811. Moreover, the cited publications are to be referred to for the explanation of all the terms not made more apparent herein.
In particular, the present invention relates to the OCF process, which was proposed for the first time in WO 88/01811.
The object of the present invention is to improve digital encoding processes and, in particular, the OCF process known from WO 88/01811 in such a manner that encoding of music of a quality comparable to compact-disc quality is possible at data rates of approximately 2 bit/ATW and of music of good FM-radio quality at data rates of 1.5 bit/ATW.